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CCS/CC1125EM-CAT1-868RD: Implementing Frequency Hopping Spread Spectrum on CC11225EM using TRx Evaluation Board

Muhammad Osama Shahid
Prodigy 70 points

Part Number: CC1125EM-CAT1-868RD

Tool/software: Code Composer Studio

Hello,

I have been trying to run the particular CC112x Software Example (http://www.ti.com/product/CC1125) of cc1120_freq_scan_mode through my TRxEB board. The code for transmission is running well (the LCD module on Evaluation Board is showing subsequent packets being sent) but the code for receiver is not running, the LCD module just shows noise on display. Also I have tried to implement Frequency Hopping using SmartRF Studio 7. The transmitter is sending the data but I dont know of any option in SmartRF Studio 7 for receiving using Frequency Hopping.

Kindly suggest what I might be missing particularly in the software example and any insight for performing receiving on SmartRF for Frequency Hopping.

Thank you,

  • 0
    TI__Guru* 83701 points

    First of all, the example SW on the web has register settings for the CC1120. Please make sure that you update the code example with settings for the CC1125 (use SmartRF Studio).

    I would recommend that you test an example that only uses one single frequency for RX and TX, to confirm that your settings and boards are working as expected.

    The reason why you only see noise on the display on the receiver, is that it has not received any packet 8LCD is not updated before first packet has been received).

    It is not possible to do any kind of frequency hopping with SmartRF Studio.

    Siri

  • 0
    Prodigy 70 points

    I have used the register settings from smartRF for CC1125 and the example for single frequency (continuous Tx-Rx in serial mode) is working fine. However when I use same settings with register value modifications in BW and Deviation for Frequency Scan example, RX gets stuck. I think The receiver is unable to detect RSSI value above a defined threshold, for any channel due to which it doesnot receive anything. 

    Any idea how to proceed in order to detect main problem.

    Thanks,

    Muhammad Osama Shahid

  • 0 in reply to Muhammad Osama Shahid
    TI__Guru* 83701 points

    Are you running the CC1125 at the same data rate as the original code runs on CC1120?

    I would assume that there are timing parameters that can be messed up if you are changing the data rate.

    Also, there are others parameters in the code that needs to be changes when changing device. At least on our HW, the CC1125 runs on 40 MHz while the CC1120 runs on 32 MHz.

    You need to go through the list below and make sure that all the defines are correct:

    /* system wide configuration defines */
#define RF_START_FREQ           902750  /* start frequency defined in khz */
#define RF_STEPSIZE_FREQ        50      /* frequency stepsize defined in khz */
#define RF_NUM_CHANNELS         50      /* number of channels in system */
#define RANDOM_SEED             250     /* used to generate hop sequence */
#define RF_XTAL_FREQ            32000   /* XTAL frequency, given in 1kHz steps */
#define LF_OSC                  32768   /* defines the Low frequency osc freq. */
#define RF_LO_DIVIDER           4       /* the value of the hardware LO divider */
#define RF_CAL_TIMEOUT          500     /* approximately 500s timeout*/

    BR

    Siri

  • 0 in reply to Siri
    Prodigy 70 points

    Thanks for your help, 

    I have been trying but I am unable to make the module work.

    Can you please suggest any transceiver Module by TI on which I could easily implement Chirp Spread Spectrum using Frequency Hopping and for which the code examples have also been provided for that particular module.

    Thanks,

    Muhammad.

  • 0 in reply to Muhammad Osama Shahid
    TI__Guru* 83701 points

    We do not have any radios supporting Chirp Spread Spectrum.

    Did you try running CC1125 using the same data rate etc. As the CC1120 example and just changing the parameters I listed?

    Siri

  • 0 in reply to Siri
    Prodigy 70 points

    Yes, I tried but still it is not receiving anything.

    Is there any transceiver module that gives FHSS without Random hopping among different channels. Actually I want to customize the hopping so that it hops among frequencies in a deterministic fashion (in linear fashion).

    Thanks,

    Muhammad

  • 0 in reply to Muhammad Osama Shahid
    TI__Guru* 83701 points

    The TI-15.4 stack for CC1310 supports FH

    but I do not know the details. I also knows that SimpliciTI supports FH

    Please note that SimpliciTI is from 2011, and support will be limited.

    You can off course also make your own solution from scratch. I am sorry that we do not have anything else to offer.

    BR

    Siri